Implant assembly device

ABSTRACT

This invention relates generally to systems for the internal fixation of bone fractures, and particularly, to equipment associated with the insertion of intramedullary fracture fixation devices such as those used in the treatment of long bone fractures, such as for example fractures of the femur, tibia, humerus, etc. An implant assembly device of the present invention may comprise a handle, a shaft with a first end and a second end, and an elongated rod extending from the shaft. The first end of the shaft is connected to the handle and the second end of the shaft is configured to engage the head of a connecting screw. The device can be held with one hand while the various components are placed one by one into their proper position onto the rod, leaving the other hand free to manipulate the other components.

RELATED APPLICATION DATA

The present application is a continuation of co-pending U.S. patentapplication Ser. No. 10/860,425, filed Jun. 2, 2004.

FIELD OF THE INVENTION

This invention relates generally to systems for the internal fixation ofbone fractures, and particularly, to equipment associated with theinsertion of intramedullary fracture fixation devices such as those usedin the treatment of long bone fractures, such as for example fracturesof the femur, tibia, humerus, etc.

BACKGROUND OF THE INVENTION

Skeletal fractures are common injuries. These fractures are typicallydebilitating and often require the patient to undergo surgery. Dependingon the severity of the fracture, the orthopedic surgeon has severaloptions for treatment, ranging from simple fracture reducing implants tocomplete prosthetic replacements. However, even when the treatment ofthe fracture does not call for a complicated procedure such as completereplacement, the proper setting of a fractured bone can still posesubstantial challenges to even the most skilled orthopedic surgeon.

The difficulties that a surgeon has to deal with when reducing afracture are well known. These difficulties include dealing with theshape and positioning of the bones or bone fragments when aligning thefracture and the accompanying complications regarding the properplacement of an orthopedic implant for supporting and holding thefracture in proper alignment until it heals. This latter problem ofimplant alignment still remains as one of the challenges facing anorthopedic surgeon in fracture surgery.

Fractures of long bones, such as the femur, are often treated with theuse of an intramedullary rod (“IM rod”) inserted into the medullarycanal of the affected bone. An IM rod, as is well known in the art,generally comprises an elongated rod along with associated cross-memberssuch as screws, tacks or nails, including nails having helical blades.The IM rod typically includes various transverse holes to allow for theplacement of the cross-members through the IM rod and into bone tissuein order to stabilize and hold together the fragmented bone segments.For example, in the treatment of fractures in the area of the neckand/or head of the femur, a lag screw or nail (with or without helicalblades) can be inserted through the proximal portion of the IM rod,across the fracture, and then into the femoral head. For more distalshaft type fractures, locking screws, bolts or nails can be placedthrough the IM rod and into bone tissue at appropriate locations inorder to provide fixation of the bone fragments.

Implanting IM rods generally involves the insertion of the rod into themedullary canal through a point located at the end of the bone. Anosteotomy is made to create an entry site and a flexible reamer isutilized to carry out the reaming of the medullary canal whileconforming to its basic anatomy. Once a suitable hole has been prepared,the IM rod is inserted through the entry site and into the medullarycanal. However, the size and shape of the IM rod can make its insertioninto the medullary canal difficult. As the IM rod may be smooth and mayhave a narrow diameter, the surgeon may not be able to achieve a tightgrip on the rod in surgery. Furthermore, a large amount of force may beneeded to push the rod into the medullary canal and the rod may alsoneed to be rotated along its axis or otherwise maneuvered to assist ininsertion, which can all make insertion difficult. In addition, thelocation of the individual holes of the rod must be identified in orderto place cross-members through the rod while it is in place within themedullary canal.

A variety of insertion systems have been developed in order tofacilitate orthopedic implant placement in bone fracture surgery. Theuse of such insertion systems have assisted orthopedic surgeons inaligning and implanting fixation implants to insure the proper healingof the fracture. For example, implant insertion handles are commonlyused to align and hold the IM rod as it is inserted into the marrowcanal of a fractured bone, and to connect to the other implant insertioninstruments, such as an aiming arm. The handle member is a curved bodywhich may have a bore located at a first end of the handle for couplingto a fixation implant and may have a plurality of bores located at asecond end of the handle. The implant insertion handle provides thesurgeon with a large grip that allows the application of a large amountof force to the IM rod, allows the rod to be easily manipulated ortwisted, and can be utilized as an alignment reference for cross-membersthat must be inserted into the bone and through the IM rod.

However, while these implant insertion handles are useful in helping toinsert an IM rod, their use requires a certain amount of preparation inthe operating room prior to the insertion of the IM rod. Once anappropriately sized IM rod has been selected by the surgeon, theinsertion handle must be properly aligned with an alignment indicator onthe proximal end of the IM rod and while the components are being heldin position, a connecting screw must be inserted through the handle andinto the IM rod. The connecting screw is then tightened with ascrewdriver or other suitable device while the components are being heldin position.

Because the various components to be connected together can be somewhatunwieldy, oftentimes the surgeon or operating room technician will havedifficulty aligning and holding the components together prior totightening the connecting screw. As described above, attaching thehandle to the IM rod requires that multiple pieces be held precisely inposition at the same time that a tool is used to tighten the connectingscrew. The difficulties inherent in assembling these components canresult in the device being dropped on the floor, thereby affecting thesterility of the instruments. In addition, components may move out ofalignment while the connecting screw is being tightened, resulting inthe handle being out of alignment with the IM rod. This can result in animproperly placed intramedullary rod or the inability to locatetransverse openings for the insertion of cross-members through the IMrod.

SUMMARY OF THE INVENTION

A preferred embodiment of an implant assembly device is disclosedcomprising a handle for manipulation by a user, a shaft having a firstend and a second end, and an elongated rod extending from the second endof the shaft. The first end of the shaft is connected to the handle andthe second end of the shaft comprises a screw engaging portion to engageand rotate a connecting screw. Also disclosed is a preferred method ofassembling an intramedullary rod and an intramedullary rod insertionhandle, comprising the steps of providing an intramedullary rod,providing an intramedullary rod insertion handle, providing an implantassembly device comprising a shaft having a first end and a second end,and an elongated rod extending from the second end of the shaft, whereinthe second end of the shaft has a screw engaging portion to rotate ascrew, placing a cannulated connecting screw onto the rod of the implantassembly device, placing an intramedullary rod insertion handle onto therod of the implant assembly device, placing the intramedullary rod ontothe rod of the implant assembly device, aligning the intramedullary rodand the insertion handle to a desired configuration, and twisting theimplant assembly device so that the connecting screw connects theinsertion handle to the intramedullary rod. Also disclosed is anembodiment of an intramedullary rod insertion kit comprising anintramedullary rod insertion handle having first and second ends, thefirst end of the insertion handle adapted to removably connect to anintramedullary rod, the intramedullary rod insertion handle having abore at its first end, a connecting screw configured to extend throughthe bore of the insertion handle and engage an intramedullary rod, theconnecting screw being cannulated and having a rotation tool engagementportion, an implant assembly device comprising a shaft having first andsecond ends, and an elongated rod extending from the second end of theshaft, wherein the second end of the shaft is configured to engage androtate the rotation tool engagement portion of the connecting screw andthe elongated rod is sized and configured to extend through theconnecting screw and the insertion handle and into the intramedullaryrod.

The implant assembly device of the present invention allows a surgeon oroperating room technician to attach insertion instruments to an IM rodwith a reduced risk of dropping the instruments or improperly aligningthe instruments with each other. The implant assembly device is designedto be used with intramedullary rods or other orthopedic fracturefixation devices, and their associated implant insertion instrumentssuch as those shown in pending U.S. application Ser. No. 10/269,976, thedisclosure of which is expressly incorporated herein by reference.

The implant insertion instruments may comprise a handle member forimplantation of a first fixation implant (or a first portion of animplant), an arm member for guiding of a second fixation implant (or asecond portion of the implant) into bone, a sleeve member for protectionof soft tissue and for translational and rotational control of thesecond fixation implant, a nut member for engaging the sleeve member,and a drive shaft with coupling member for attachment to the secondfixation implant and for driving the second fixation implant through thearm member and sleeve member into the fractured bone. The implantinsertion instruments may also include a striking member to aid thesurgeon in inserting the first fixation implant into the fractured bone.A measuring device that reduces measuring errors made by a user and ameasuring device that determines implant length, diameter, and angle ofinsertion may also be included. These implant insertion instruments mayhave a bore running though them (known as a cannulation) that allowsthem to be placed over a guide wire or a push rod during insertion.

The implant assembly device of the present invention allows the surgeonor operating room technician to easily and securely attach an implantinsertion instrument to an intramedullary rod by holding the variousrelated components aligned and in position on a pushrod while aconnecting screw is locked into position. The device can be held withone hand while the various components are placed one by one into theirproper position onto the pushrod of the device, leaving the other handfree to manipulate the other components. When all of the pieces are inposition, an integrated screw engaging portion of the rod fits into theconnecting screw and allows the user to tighten the screw simply byturning the handle to complete the assembly. The implant assembly deviceis then removed from the device and the intramedullary rod is ready forinsertion into the fractured bone.

An implant assembly device of the present invention may comprise ahandle, a shaft with a first end and a second end, and an elongated rodextending from the shaft. The first end of the shaft is connected to thehandle and the second end of the shaft is configured to engage the headof a connecting screw. In one embodiment of the implant assembly device,the handle is spherical and is provided with a plurality of surfacegrooves. In another embodiment of the implant assembly device, thehandle is spherical and is provided with a grippable surface and thesecond end of the shaft has a hexagonal, square, Torx™, spline, or keyedshape for engaging the head of a connecting screw. The handle may becomposed of AL 6061-T6 aluminum alloy, and may also be provided with aplurality of gripping inserts. The shaft may be composed of Grade 431stainless steel, and is preferably about 40 mm long, although the lengthmay be longer or shorter as necessary. The elongated rod extending fromthe shaft may be between 50 mm and 400 mm long and may be composed ofGrade 316 stainless steel.

An alternative embodiment of the implant assembly device may have ahandle integrally formed with a shaft that extends from the handle, ascrew-engaging portion formed on the end of the shaft; and an elongatedrod extending from the shaft. The shaft may be removably attached to thehandle and the rod may be removably attached to the shaft. Optionally,the rod and shaft may be integrally formed with a screw engaging portionlocated between the ends of the integral rod/shaft. The elongatedintegral rod/shaft may also be removably attached to the handle. Thehandle may be spherical and may be provided with a plurality of surfacegrooves, and the screw-engaging portion of the shaft may have ahexagonal, square, Torx™, spline, or keyed shape.

The implant assembly device may be used to assemble an intramedullaryrod and a handle by: choosing an appropriately sized intramedullary rod;placing a cannulated connecting screw onto a rod of an implant assemblydevice; sliding the cannulated connecting screw along the rod so thatthe connecting screw engages a screw engaging portion of a shaftextending from a handle of the implant assembly device; placing anintramedullary rod insertion handle onto the rod of the implant assemblydevice; sliding the insertion handle along the rod so that theconnecting screw engages the insertion handle, placing theintramedullary rod onto the rod of the implant assembly device; slidingthe intramedullary rod along the rod to engage the insertion handle;aligning the intramedullary rod and the insertion handle to a desiredconfiguration; and twisting the handle of the implant assembly device totighten the connecting screw so that the insertion handle is secured tothe intramedullary rod.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed figures are for purposes of description and may illustratepreferred features of the implant assembly device which may be optional,and which further may be combined or used singularly. These figures areintended to be illustrative only and in no way serve to limit the scopeof the invention. The present invention is limited only by the claims.

FIG. 1 is a plan view of an exemplary embodiment of the implant assemblydevice of the present invention.

FIG. 2 is a perspective view of the exemplary embodiment of the implantassembly device of the present invention.

FIG. 3 is a perspective view of an IM rod, an insertion handle and aconnection screw in a partially assembled configuration, mounted on theimplant assembly device.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 3 shows the preferred embodiment of the implant assembly device 10,along with an IM rod 20 and various components that may be associatedwith the insertion of an IM rod. FIG. 3 shows a connecting screw 13 andan insertion handle 12 in a partially assembled configuration as each isplaced on the device 10 prior to being locked into position on the IMrod 20.

As illustrated in FIGS. 1 and 2, handle 1 is preferably connected to ashaft 2 that extends from the body of handle 1. The handle 1 preferablyis of an appropriate size and shape to be easily gripped by a user andto allow the user to apply a rotational force to the device. While thehandle is shown in a generally spherical configuration, the handle mayalso be of any shape that preferably allows the user to grip the device.The handle may be provided with grooves or other form of surfaceirregularities or texturing to improve the gripping qualities of thehandle. The handle may alternatively be provided with a surfacetreatment, covering, or inserts which likewise improve the grippingqualities of the handle. The handle may be composed of an aluminum alloysuch as AL 6061-T6, but other suitable materials, both metallic andnon-metallic, may be used. The handle may also be substantially hollow,with or without an opening to the exterior.

To securely hold shaft 2 within the handle 1, a pin 6 or otherappropriate mechanism preferably extends through the handle 1 and intoor against shaft 2. Securing the shaft 2 to the handle 1 can also beaccomplished by other means known to those of skill in the art. Forexample, shaft 2 may be provided with a threaded surface which engages asimilarly threaded bore present in the handle 1, the shaft 2 may bepress fit into handle 1 or otherwise welded, brazed or cementedtogether. In another embodiment, the shaft 2 is integrally formed withthe handle 1, thereby providing a single piece shaft/handle unit.

The shaft 2 is preferably composed of an appropriate metal or metalalloy, such as Grade 431 stainless steel, although other materials whichexhibit the properties desired by a user could conceivably beimplemented as well. Shaft 2 has first 8 and second 9 ends, and a lengthL1. Length L1 may be from 10 mm to 100 mm, and most preferably is 40 mm.Shaft 2 may have a circular cross-section and may have a diameter thatis sized as required to provide a screw engaging portion 7 appropriateto engage the screw to be used. Most preferably, the diameter of theshaft 2 is approximately 9 mm. Understandably, larger or smallerdiameter shafts 2 may be used as required. In addition, while shaft 2has been described as having a circular cross-section, it may beprovided in other shapes as well. The first end 8 of shaft 2 preferablyhas a screw engaging portion 7 preferably in the shape of a hexagonalsection which is designed to engage the corresponding preferablyhexagonal inset found in the head 14 of a connecting screw 13. Thesecond end 9 of the shaft 2 is inserted into the handle 1 of the implantassembly device 10. Other sizes, shapes or configurations of theengaging portion 7 of the shaft 2 can also be used as appropriate toengage the head 14 of a connecting screw 13. For example, the end ofshaft 2 may have a square, Torx™, spline, star, or keyed shape forengaging the head 14 of a connecting screw 13 and applying the desiredrotation to the screw. Shaft 2 may also be solid or cannulated asdesired.

Preferably, an about 3.0 mm diameter rod 4 extends from shaft 2. The rod4 is similar to the guide rods commonly used in orthopedic surgery toalign and position implants inserted into bones. However, the rod 4 maybe of a smaller or larger diameter, or solid or hollow, as required,without detracting from the operation of the device. In addition, whilethe rod has been described as having a diameter with a circularcross-section, one skilled in the art will appreciate that other shapesand configurations may be used for rod 4 such as, for example, a squarecross-section, an “I” cross-section, a “C” or “T” cross-section, etc.The rod 4 is preferably made of Grade 316 stainless steel, however,other metals, metal alloys, or other types of materials which exhibitthe appropriate properties may also be used.

The rod 4 has first 15 and second 16 ends, and a length L2. The rod 4preferably is sufficiently stiff to support the various componentsplaced upon it, while at the same time exhibit a certain amount offlexibility to accommodate the bends or curvatures of the IM rod orinsertion components. The length L2 of rod 4 is preferably about 250 mmto about 350 mm, and more preferably about 320 mm long, although thelength of the rod 4 may be longer or shorter as necessary to meet thedemands of the implant instruments. For example, rods of approximately50 mm in length may be used to assemble insertion handles with solid IMrods with a limited length bore at its proximal end.

The rod 4 is preferably connected to the shaft 2 by brazing before theshaft is inserted into the handle. In another embodiment, the rod 4 issecurely held by the shaft 2 by a pin extending through the handle 1 andshaft 2, into or against the rod 4. It is contemplated that the rod 4can be held in the handle 1 by other means known to those of skill inthe art. For example, the rod 4 may be press-fit into the shaft 2 andheld only by the frictional fit within the shaft 2. The rod 4 may alsobe threaded or otherwise prepared to interconnect with the shaft 2. Inanother embodiment, the rod 4 may be configured to be removablyconnected to the shaft 2, thereby allowing the use of different lengthrods as required under the circumstances. Alternatively, the rod andshaft can be formed as an integral piece, with the screw engagingportion 7 being located between the ends 9, 15 of the integralrod/shaft.

During the course of surgery to fix a fracture, the surgeon maydetermine the appropriate length and diameter IM rod to be used basedupon the physical characteristics of the patient. To connect the chosenIM rod to the insertion handle 12, the surgeon or operating roomtechnician then slides a cannulated connecting screw 13 onto the rod 4of the implant assembly device 10. The connecting screw 13 preferablyhas a bore forming the cannulation, the bore preferably being about 1 mmto about 10 mm, and most preferably greater than about 3 mm. Theconnecting screw 13 preferably has threads at its first end to engagethreads formed in the more of the intramedullary rod, and a rotationtool engaging portion preferably in the form of a shaped recess at itssecond end for engagement with the screw engaging portion 7 of theimplant assembly device 10. An insertion handle 12 with a first end 18,a second end 17 and a bore 19 is then placed over the rod 4, followed bythe IM rod 20 being placed over the rod 4. Other components to beattached to the IM rod 20 and the insertion handle 12, such as thosedescribed above, can also be placed on the rod 4 of the implant assemblydevice 10 at this time in the desired sequence. Because the variouscomponents are being supported by the rod 4, the task of the operatingroom technician is greatly simplified. The implant assembly device 10can be held in one hand with a reduced chance of dropping one of thevarious components that are placed on the rod 4. Once all the pieces arein position, the IM rod 20 and insertion handle 12 may be carefullymanipulated (i.e. rotated) about the rod 4 into proper alignment witheach other. Other components can also be aligned at this time asdesired. Following the alignment of the various components, the IM rod20 and the insertion handle 12 are connected to each other by rotatingthe ball handle 1 to tighten the connecting screw 13. More specificallythe screw engaging portion 7 of the shaft 2 engages the connecting screw13. It is not necessary for the operating room technician to remove hishands from the assemblage to reach for an additional tool to lock theconnection screw into position, but instead the handle 1 need only berotated to tighten the cannulated connecting screw 13.

While it is apparent that the illustrative embodiments of the inventionherein disclosed fulfill the objectives of the disclosed invention, itwill be appreciated that numerous modifications and other embodimentsmay be devised by those skilled in the art. Therefore, it will beunderstood that the appended claims are intended to cover all suchmodifications and embodiments which come within the spirit and scope ofthe present invention.

1. An implant assembly device for use in inserting a bone fixationimplant comprising: a handle portion for manipulation by a user, a shafthaving a first end and a second end, the first end of the shaftconnected to the handle portion and the second end of the shaftincluding a screw engaging portion configured and adapted to engage androtate a connecting screw, and an elongated rod extending from thesecond end of the shaft, the elongated rod configured and dimensioned tosimultaneously pass through an interior portion of, and support, animplant insertion handle, the connecting screw and the bone fixationimplant.
 2. The implant assembly device of claim 1, wherein the handleportion is substantially spherical and is provided with a plurality ofsurface grooves.
 3. The implant assembly device of claim 1, wherein thescrew engagement portion has a shape selected from at least one of thegroup consisting of a hexagon, square, star, spline, and keyed shape forengaging the head of the connecting screw.
 4. The implant assemblydevice of claim 2, wherein the handle portion is composed of AL 6061-T6aluminum alloy.
 5. The implant assembly device of claim 1, wherein thehandle portion is provided with a plurality gripping inserts.
 6. Theimplant assembly device of claim 1, wherein the shaft has a length ofbetween about 10 mm and about 100 mm.
 7. The implant assembly device ofclaim 6, wherein the elongated rod extending from the shaft is betweenabout 50 mm and about 400 mm long.
 8. The implant assembly device ofclaim 7 wherein the elongated rod has a diameter of between 1 mm and 10mm.
 9. The implant assembly device of claim 1 wherein the handle portionis integrally formed with the shaft.
 10. The implant assembly device ofclaim 1, wherein the elongated rod is removably attached to the shaft.11. The implant assembly device of claim 1, wherein the shaft isremovably attached to the handle portion.
 12. The implant assemblydevice of claim 1, wherein the rod is integrally formed with the shaftand the screw engaging portion is positioned between the ends of the rodand shaft.
 13. The implant assembly device of claim 1 wherein the screwengaging portion is positioned about 200 mm to about 350 mm from the endof the rod.
 14. An implant assembly device for use in inserting a bonefixation implant comprising: a handle portion for manipulation by auser, a shaft having a first end and a second end, the first end of theshaft connected to the handle portion and the second end of the shaftincluding a screw engaging portion configured and adapted to engage androtate a connecting screw, and an elongated rod extending from thesecond end of the shaft, the elongated rod configured and dimensioned tosimultaneously pass through an interior portion of, and support, animplant insertion handle, the connecting screw and the bone fixationimplant wherein a distal end of the elongated rod is non-threaded. 15.The implant assembly device of claim 14, wherein the handle portion issubstantially spherical and is provided with a plurality of surfacegrooves.
 16. The implant assembly device of claim 14, wherein the handleportion is integrally formed with the shaft.
 17. The implant assemblydevice of claim 14, wherein the elongated rod is removably attached tothe shaft.
 18. The implant assembly device of claim 14, wherein the rodis integrally formed with the shaft.
 19. A bone fixation implantinsertion kit comprising: a bone fixation implant; an implant insertionhandle having a first end configured and dimensioned for removableattachment to the bone fixation implant; a connecting screw having afirst end configured and dimensioned for joining the insertion handle tothe bone fixation implant; and an implant assembly device including ahandle portion for manipulation by a user, a shaft having a first endand a second end, the first end of the shaft connected to the handleportion and the second end of the shaft including a screw engagingportion configured and adapted to engage and rotate the connectingscrew, and an elongated rod extending from the second end of the shaft,the elongated rod configured and dimensioned to simultaneously passthrough an interior portion of and support the insertion handle, theconnecting screw and the bone fixation implant.
 20. The bone fixationimplant insertion kit of claim 14, wherein the implant insertion handlefurther comprises a mounting for the attachment of an aiming arm.